import type { CreateNodeContext } from '../doc/createNode.ts'
import type { Node } from '../nodes/Node.ts'
import type { Scalar } from '../nodes/Scalar.ts'
import type { YAMLMap } from '../nodes/YAMLMap.ts'
import type { YAMLSeq } from '../nodes/YAMLSeq.ts'
import type { ParseOptions } from '../options.ts'
import type { StringifyContext } from '../stringify/stringify.ts'
import type { Schema } from './Schema.ts'

interface TagBase {
  /**
   * An optional factory function, used e.g. by collections when wrapping JS objects as AST nodes.
   */
  createNode?: (schema: Schema, value: unknown, ctx: CreateNodeContext) => Node

  /**
   * If `true`, allows for values to be stringified without
   * an explicit tag together with `test`.
   * If `'key'`, this only applies if the value is used as a mapping key.
   * For most cases, it's unlikely that you'll actually want to use this,
   * even if you first think you do.
   */
  default?: boolean | 'key'

  /**
   * If a tag has multiple forms that should be parsed and/or stringified
   * differently, use `format` to identify them.
   */
  format?: string

  /**
   * Used by `YAML.createNode` to detect your data type, e.g. using `typeof` or
   * `instanceof`.
   */
  identify?: (value: unknown) => boolean

  /**
   * The identifier for your data type, with which its stringified form will be
   * prefixed. Should either be a !-prefixed local `!tag`, or a fully qualified
   * `tag:domain,date:foo`.
   */
  tag: string
}

export interface ScalarTag extends TagBase {
  collection?: never
  nodeClass?: never

  /**
   * Turns a value into an AST node.
   * If returning a non-`Node` value, the output will be wrapped as a `Scalar`.
   */
  resolve(
    value: string,
    onError: (message: string) => void,
    options: ParseOptions
  ): unknown

  /**
   * Optional function stringifying a Scalar node. If your data includes a
   * suitable `.toString()` method, you can probably leave this undefined and
   * use the default stringifier.
   *
   * @param item The node being stringified.
   * @param ctx Contains the stringifying context variables.
   * @param onComment Callback to signal that the stringifier includes the
   *   item's comment in its output.
   * @param onChompKeep Callback to signal that the output uses a block scalar
   *   type with the `+` chomping indicator.
   */
  stringify?: (
    item: Scalar,
    ctx: StringifyContext,
    onComment?: () => void,
    onChompKeep?: () => void
  ) => string

  /**
   * Together with `default` allows for values to be stringified without an
   * explicit tag and detected using a regular expression. For most cases, it's
   * unlikely that you'll actually want to use these, even if you first think
   * you do.
   */
  test?: RegExp
}

export interface CollectionTag extends TagBase {
  stringify?: never
  test?: never

  /** The source collection type supported by this tag. */
  collection: 'map' | 'seq'

  /**
   * The `Node` child class that implements this tag.
   * If set, used to select this tag when stringifying.
   *
   * If the class provides a static `from` method, then that
   * will be used if the tag object doesn't have a `createNode` method.
   */
  nodeClass?: {
    new (schema?: Schema): Node
    from?: (schema: Schema, obj: unknown, ctx: CreateNodeContext) => Node
  }

  /**
   * Turns a value into an AST node.
   * If returning a non-`Node` value, the output will be wrapped as a `Scalar`.
   *
   * Note: this is required if nodeClass is not provided.
   */
  resolve?: (
    value: YAMLMap.Parsed | YAMLSeq.Parsed,
    onError: (message: string) => void,
    options: ParseOptions
  ) => unknown
}
